Pump



Oct. 21, 1958 R. B. SAALFRANK' PUMP 2 Sheets-Sheet 1 Filed June 5. 1953 MM. NM

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Oct.A 21, 195s R. B. SAALFRANK .PUMP

2 Sheets-Sheet 2 `Filed June 5. 1953 R TN ggg/22?:

United States Patent 2,856,857 PUMP Royal Bartlett Saalfrank, Gulfport, Fla., assignor to Milton Roy Company, Philadelphia, Pa., a corporation of Pennsylvania Application June 5, 1953, Serial No.v 359,843

8 Claims. (Cl. 10S-44) The present invention relates to pumps, and particularly to accurate metering pumps of positive displacement type for use in dispensing chemicals and other liquids.

A purpose of the invention is to connect a mechanical drive including a plunger to a moving wall of a pump such as a diaphragm or bellows by means of a motiontransmitting liquid, and to correct on each cycle of pump operation for expansion and contraction of the liquid so as to prevent any error due to this cause.

A further purpose is to provide a passage to atmosphere from the liquid interconnecting a pump plunger and a moving wall, and locate a check valve in this passage so that during the suction stroke the liquid is connected to atmosphere and adjustment due to expansion and contraction can occur.

A further purpose is to lead the expansion and contraction adjustment passage through the plunger and place the check valve itself in the plunger.

A further purpose is to provide drag between the valve element and the side wall and to manipulate the valve opposite to the direction of motion of the plunger by the drag so that the valve closes in one direction when the plunger advances to prevent escape of iluid from the space ahead of the plunger and closes in the opposite direction when the plunger retracts, but is momentarily fully open at the end of each stroke.

Further purposes appear in the specication and in the claims.

in the drawings, I have chosen to illustrate a few only of the numerous embodiments in which my invention may appear, selecting the forms shown from the standpoints of convenience in illustration, satisfactory operation and clear demonstration of the principles involved.

Figure 1 is a central vertical longitudinal section of a pump in accordance with the invention, shown on the compression stroke.

Figure 2 is an enlarged `fragmentary view similar to Figure l, showing the suction stroke.

Figure 3 is a top plan view of Figure 1.

Figure 4 is a central vertical longitudinal section corresponding to Figure l but showing a variation.

In the chemical industry extensive use is being made of pumps which meter and accurately dispense liquids such as chemical solutions to processing equipment and the like. It is very desirable to have a high degree of accuracy in such cases, in order to improve the control of the process employed. Pumps having moving walls such as diaphragme and bellows are extensively employed for this purpose.

Mechanical interconnection to bellows or diaphragms, however, is objectionable, as it subjects the moving wall to vibrational forces present in the drive, restrains the moving wall and thus is likely to cause earlier failure, and subjects the moving wall to any irregularities of motion due to imperfections in the driving mechanism. It is very desirable, therefore, to interpose a driving icc liquid between a reciprocating member such as a plunger and the moving wall so that mechanical variations can be smoothed out and operation can become more uniform, with increased life of the diaphragm or bellows.

Unfortunately, however, the liquid employed in the drive is subject to variations in temperature, both due to change in ambient conditions and also on account or" the temperature of the liquid pumped and heat developed from friction in the driving liquid itself and in the related equipment.

Whenever the temperature of the driving liquid changes, its volume changes due to expansion or contraction, and the volume discharge on each cycle of the pump changes, introducting an error which in some cases is serious and in all cases objectionable.

In accordance with the present invention, I connect the driving liquid to atmosphere at least once in each cycle and thus allowfor correction due to expansion or contraction, since the quantity of liquid in the driving space can re adjust.

As shown in Figures l to 3, a pump chamber 20 has a suitably cylindrical xed wall 21, end walls 22 and 23 and a moving wall or bellows 24 which extends in from and is secured to the end wall 22 and has its forward end closed by a head 25 and a plug 26. The bellows is suitably a resilient metallic bellows of beryllium copper Phosphor bronze, stainless steel or the like.

Two inlet ball check valves 27 and 28 in series connect from an inlet connection 30 to an inlet port 31 into the pump chamber near the bottom. Similarly, two outlet ball check valves 32 and 33 in series connect from an outlet port 34 near the top of the pump chamber to an outlet connection 35. The valves are suitably all alike and comprise upwardly directed seats 36 and balls 37 on the seats limited in upward motion by limiter plugs 38 which are suitably threaded into the valve casings above the balls. i

There is'suitably a continuous upward ow of the pumped liquid from the inlet connection through the pump to the outlet connection.

The pump is desirably driven from any suitable drive, desirably a motor through gearing to a crank and connecting rod (not shown) as well known, which reciprocates a pump plunger 40 suitably of cylindrical shape guided in a forward guide or cylinder 41 and a rearward guide 42 to move toward and away from the moving wall. Suitable packing is provided at 43 to prevent leakage of the driving liquid. Around the plunger inside a housing 44 an oil or other liquid reservoir 45 is provided having a stand pipe connection 46 to the atmosphere at the top, extending above the inside space of the bellows.

A passage extends from the reservoir 45 to space 47 inside the bellows which is filled with the driving liquid. The driving liquid will ordinarily be oil but in certain cases special liquids may be used, such as mixtures of glycerine and water in any proportions or any other suitable hydraulic liquid.

On the forward end of the plunger is mounted a valve stem or projection 51 threaded at 52 into the end of the plunger, having a conical seat 53 which is nearest the end of the plunger, having an intermediate barrel 54 and having an opposed conical seat 55 which is .most remote from the end of the plunger. The passage 48 is extended at 56 through the male threaded portion of the seat projection, and communicates with radial passages 57 which connect the passage 4S with the space 58 ahead of the plunger and around the seat 53. The seat 55 is preferably removable, being held in place by nut 60 on the end of threaded stud 61 extending from the barrel 54. p

3 rounds the barrel and hasexposed shoulders 63 and 64 whichin 'opposite positionsv engage andseal against'the respective seats 53 and 55.

An annular groove 65 extends around the middle of the' outside of the valve sleeve, andreceives' an Orin'g\66 suitably'of Vrubber or synthetic rubber 'which frictionally engages 'the 'inside'wall f 'the tubular 'guidef41, thus a'cting as a restraining means' on the' valvesleeve' by tending tornake the'valve sleeve move in the direction'opposite tof the'mo'tion of the plunger due torricti'onaldrag. h.

InV operation of the form ofFiguresl' to 3, it will be understood that "when thefpurnp is operating the space"47 inside the' bellows'fandall` 'of the passagesthroughto the reservoir and the lower part of the`star1dp'ipe*arefilled with hydraulic liquid. vThis includes'space 67"i`ns`ide the valve sleeve and -b'e'tween the valve "sleeveand the barrel 54. 'At each reciprocation 'whenthe plunger reverses direction the valve sleeve travels to the' position-of engagement with the opposite seat,'sin'ce the'plungier is moving and the' O-'ring'causes the'valve to `fricti'onally drag on the inside wall of the guide '41. "Thusin Figure l onfthe compression stroke wherethe plunger ismovingtoward the right, and valve shoulder 63 is closed against valve seat 53. On the other hand in Figure 2 when 'the plunger is moving tothe left, on the 'suction stroke of the pump, the drag of -'ring 66 shiftsthe valve sleeve to the right, closing shoulder 64 against seat 55.

At the end of each strokewhen the plunger is reversing for a short interval the valve is open at'seat 53 and also at seat-S5 and during this'interval volume changes by expansion or contraction of the hydraulic liquid take place, thus correcting automatically for anyl effect of change in temperatur'efor change in volume.

The device is equally effective lwhen used in connection with a diaphragm instead of a bellows. In Figure 4 I illustrate such a modification, with the same plunger, check valve and passage arrangement. The diaphragm 24', suitably of rubber in this case, forms the moving wall of the pump chamber Ztl', and the diaphragm is protected in its two limiting positions by spaced perforated walls 68 and 70 as well known. Except that the chamber varies in shape, having a short cylindrical portion 21,and large end walls 22 and 23-,the constructionis generally similar to that of Figures l to 3, and the functioning of the check valve is the same.

Inview of my invention and disclosure variations and modications 'to Vmeet individual whim or particularfne'ed will 'doubtless'become evident to others skilled'in the art, tofobtainall orpart ofthe benefits 'of my invention with out copying thes'tructure shown, and I, ltherefore, claim all such insofar as they fall 'within Ythereasonable spirit and `scopefof fm-y claims.

It will be evident lof course that the valve may if desired `be loperated due lto yinertia or a combination of inertia and friction, or due tofany other retardingforce.

Having thus described my invention what I claim as new andtdesire tosecure by Letters Patent is:

l. -In pump mechanism, ya pump having a moving wall and having a pump chamber on one side of the moving wall, a. cylinder communicating with the-side' of the moving wall remote from pump chamber, a plunger-reciprocable in the cylinder toward and away from the V`Vmoving wall, there being a liquid extending 4Vfromthe'plunger through the cylinder to the moving wall, aconduitconnectin'g at oneen'd with th'efliquid between the plunger'and the moving wall land at theother end with the atmosphere, and a check :valve `in the conduit .having opposed lseats and interconnected opposed valve elements cooperating with the respective seats, said valve elements being carried l-by said .plunger and reciprocable therewith relative tosaid moving wall. V

2. -In a pump mechanism, a pump -having a moving wall and having a pump chamber on one side of the moving wall, a cylinder connecting with the side of the moving wall remote from the pump chamber, `a .plunger reciprocable in the cylinder toward and away-from -the moving "wall, there being Aa -liquid extending from -the plunger through the cylinder' to the moving Wall, a conduit extending through the plunger connecting at one end with the liquid between plunger and the moving wall and at the other end with the atmosphere, and a check valve in the conduit having opposed-seats and interconnected opposed valve elements cooperating with the respective seats.

T A pump mechanism of claimZ,v in which theA moving wall is'abellows.

4. A pump mechanism of claim 2, in which-the moving wall is a diaphragm. A

5. Apump mechanism "'of claim 2, inl combination with friction means onthe'valve elements engaging the interior oi the cylinder.

o'. A pump mechanism of claim 2, in which the opposed vseats are connected by a stem and in which the valve Aelements are y` of ring formation surrounding the stern, in*'combinationifwitharictional element operating betweenthe valve FVelements Iand the cylinder.

7. A pump mechanism comprising a pump havinga moving wallandta pump chamber on one side of` said movingwall;housing 'Structure forming a chamber` for a motion-transmitting'liquid andcornmunicating with 'the oppos'itef'side of'saidm'oving wall, a plunger'reciproc'able insaid'hous'ing' chamber toward andV away' from said moving wall, avrriotiontransmitting` liquid in said' housing chamberfor'transmitting motion from said plunger 'to saidmovin'gwall" to perate'said pump, a ilow connection extendingf'froml'a reservoir Yof said liquid which is open tot'atmosphere'to ``a location in said 'housing' chamber between said plunger'and'saidmoving"wall, and valve means controlling said flow connection and carried by said plungeribetw'een said moving 'wall and said ow connection selectively to seal said'liquid communicating with said moving'wall with respect to atmosphere, said valve means'being' in closed position during the forward and reverse strokes'of said plunger to close said ilow connection "withrespect to said moving wall and seal said liquid within'sa'i'd housing chamber in communication with "said 'mvingwall between said'valve means and said moving wall, said' valve means being moved by saidplungerduring reversal at the end of each stroke to r open positiontto opensaidiilo'w connection with respect to "said moving 'wall Vva'n'd 'connect said liquid in said housing chamber communicating with said moving wall with the'frse'ivoir"audatriosphee to permit readjustment ofthe'volu'mle fsaid liquidiinsaid'housing chamberdue to Vany 'eiipasion or contraction ofI said liquid.

8. A pump "mechanism comprising a pump having va moving walland'a pump chamber on one side of said moving wall, housing structure forming a chamber'having tn'otio'nltran'smitting'liquid and communicating with the opposite side of said moving wall, a plunger reciprocable in said housing chamber towards and away'from said moving wall,`a motion-transmitting liquid in said housing chamber for transmitting motion from 'said plunger to 'said moving wall to operate said pump, a flow corinectio'niextending'from'a reservoir of said liquid which is open to 'atmosphere to a location in said housing chamber between 'said -plunger and said moving wall, valve-meansin said-ow lconnection and carried by said plunger selectively to seal ysaid liquid communicating with said l:moving walll with respect to atmosphere, 'and restraining means -effectiveon said valve means to cause said valve means to be moved by said plunger momentarily to yopen position at the end of astroke independently of the pressure on said liquidrcommunicating with said moving wallto open-'said ow connection with respect to said moving Wall and connect said liquid in said `hou-sing chamber communicating with said Umoving wall with `the :reservoir-and atmosphere vat least once-in each cycle of -said Y:pump yto eperrnit 'readjustrnent' of Ithe 5 volume of said liquid in said housing chamber due to any 1,101,266 expansion or contraction of said liquid. 2,303,597 2,578,746 References Cited in the le of this patent UNITED STATES PATENTS 272,374

862,867 v Eggleston Aug. 6, 1907 Franklin June 23, 1914 Adelson Dec. 1, 1942 Scherger Dec. 18, 1951 FOREIGN PATENTS Great Britain June 16, 1927 

